Lilacs provide a beautifully flowering and powerfully scented shrub for the spring garden. The common Lilac generally flowers in mid-May to early June in hardiness zones 3 and 4, earlier in the higher zones. But there are many different kinds of Lilacs and they flower at different times. Hyacinthiafloras are among the Early Lilacs that generally flower 10 days to 2 weeks earlier than the common Lillac. The Prestons are among the Late Lilacs that generally bloom 10 days to 2 weeks later than the common Lilac. Then there are the Lilac Trees which bloom about 4 to 6 weeks after the common Lilac.
Lilac flowers come in a great variety of colors. They are catagorized into 7 groups, White, Violet, Blue, Lilac, Pink, Magenta and Purple. There are many Lilacs that are hard to put into one catagory, and several that have more than one color.
The famous Lilac scent also varies greatly, from none to very heavy. Check the tag for the fragrance value of the plant your considering
Lilacs generally are in hardiness zones 3-7 but some extend into zone 9 and a few start in zones 4 and 5.
Lilacs enjoy full sun, if the area you are planting your Lilac is shady or receives only afternoon sun consider another spot. Morning sun is important to dry out the plant to prevent mildew. Lilacs also like a well drained soil. Planting on slopes or mounding the area under your plant will improve the plants ability to thrive. Be sure to look around for that growing tree that may eventually shade your plant.
A common Lilac usually grows to 10-12 feet, but there are many Lilacs and their growth habit varies greatly. As a general rule, a Lilac needs 6 feet in diameter for every 10 feet in height, but be sure to read the tag on your plant which should have specific instructions. The diameter of a plant is measured at the "drip line". The drip line is the furthest extent of the branches; so the diameter of a plant at the drip line would be measured from branch tip on one side of the plant to the branch tip on the opposite side of the plant.
At a minimum leave 2-3 feet of space between plants at their drip lines when they would be mature. This also applies when planting next to buildings and fences. Reflecting sun from buildings creates "microclimates", which can increase heat and reduce beneficial winds. Therefore, a commom Lilac that will be 10 ft in height and 6-8 ft in diameter (at the drip line) should be planted 11 to 12 ft from any building. You should also insure that snow or ice that falls from the roof won't fall on the plant. Excessive water from roof run off must also be avoided. If you have a dryer vent, or gas heating appliance vent, plant 10 ft away from the heat blast area to avoid excessive fungal growth..
Once you have decided on the color, height, placement and spacing of your Lilac, you now must select an actual plant. The most obvious place is your local nursery. If you have a nursery in your area that specializes in Lilacs or carries a large selction, that would be the best place to start. But like all plant selections take your time and invesitgate more than one option. Look for plants that have a good trunk (called canes), more than one cane is okay. Look for shape, dead or dying leaves and dead or stubbed branches, this will indicate the care the plant has received until now. Usually the most important factor is the reputation of the nursery. Expect to pay $40-$70 for a 3 year old (5 gal) plant. Of course this varies greatly from area to area and the rarity of the plant.
Many people like to buy a plant that is well along in its development, say 6 or more feet in height. These plants become very expensive and can cost several hundred dollars. Beware that there are disadvantages to buying these plants, such as already established growth habit, limited root growth (many are heavily root bound and require root pruning) and special care to insure survival in the first year or two. Smaller plants in the 2-3 foot range are the easiest to plant and with routine care should grow and thrive.
Other options are to obtain a "sucker" from another plant or do a "cutting". Suckers are new canes being produced by the plant, they can easily be dug up and transplanted. Cuttings involve cutting a small part of a branch of a plant, applying a process to that cutting and planting it in a small pot. You can also buy plants bare-root (usually through the mail), many catalogs are now on-line. Some nurseries also carry one and two year old plants at a very reasonable price (usually $10-$20).
Other places to look are plant sales at public gardens, arboratums, Garden Clubs, horticulture centers and farms, and museum gardens. Mass discount garden centers are popular and cheap, but you get what you pay for. Common problems are that the plant doesn't turn out to be the plant clamied, they have a high incidence of failure and are poorly formed as they grow. You won't know what the plant is until it flowers which is usually in the 4th or 5th year of growth.